Information signal processing unit

ABSTRACT

A new additional information generating section generates new additional information FS 1  based upon information from an additional information reading section. The spectrum of the new additional information FS 1  is spread by an SS additional information generating section and supplied to a signal superimposing section as SS additional information SF 1.  The signal superimposing section generates a digital video signal S 2  by superimposing the SS additional information SF 1  on a digital video signal S 1.  A writing section records the digital video signal S 2  on which the SS additional information SF 1  is superimposed on a recording medium. Hereby, adding additional information to an information signal without deteriorating the quality of the read information signal so that the falsification and deletion are disabled, detecting the additional information added to the information signal if necessary and utilizing it are enabled.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an information signal processingunit for detecting additional information from an information signal towhich the additional information is added and processing it.

[0003] 2. Description of the Related Art

[0004] Recently, a reproducing unit for a digital video tape recorder(VTR) and a digital video disc (DVD) and software reproducible usingthese units are provided in numbers, digitized video signal and auralsignal can also be reproduced readily at home, and an image and asound/voice respectively excellent in the quality of an image and asound/voice can be reproduced.

[0005] Digitized video signal and aural signal or a program areplentifully provided via a recording medium such as the Internet and acompact disc read only memory (CD-ROM) and digitized software providedvia the Internet, CD-ROM and others is widely utilized using a personalcomputer and others.

[0006] However, in the meantime, there is a problem that softwareplentifully provided as described above and composed of digitized videosignals and others may be unlimitedly copied. Therefore, if digitizedinformation, for example a video signal is dealt with, direct copypreventing control such as copy prohibition is executed by adding a copypreventing code to a digital video signal as digital data and recordingit on a recording medium.

[0007] Not only a copy preventing code for prohibiting or allowing copyis added but a code for limiting the generation of copy is added to adigital video signal and more flexible control over copy is alsoexecuted.

[0008]FIG. 1 is a basic block diagram showing a copy system in casedigitized information is dealt and the copy system is provided withfunctions for sending digital information read by a digital informationreading device 110 to a digital information recording device 120,copying information which can be copied, prohibiting the copy ofinformation the copy of which is not allowed and updating the followingdigital information in case a code for limiting the generation of copyexists in digital information.

[0009] Copy control information as additional information is recorded inaddition to digital main information in a recording medium 111 installedin the digital information reading device 110. The copy controlinformation is provided with the prohibition or allowance of copy, thelimitation of a generation and others as control contents.

[0010] The reading section 112 of the digital information reading device110 generates a digital read information signal D2 composed of digitalmain information and copy control information added to the digital maininformation based upon a signal D1 obtained by reading information inthe recording medium 111 and sends the above signal to the digitalinformation recording device 120.

[0011] The additional information reading section 121 of the digitalinformation recording device 120 detects copy control information CCfrom the received digital read information signal D2 and sends thedetected copy control information CC and the digital read informationsignal D2 to an additional information changing section 122.

[0012] The additional information changing section 122 generates newadditional information based upon copy control information CC in casecopy control information added to a digital information signal D2 isrequired to be changed and changes copy control information added to thedigital information signal D2 by adding the new additional informationto the digital information signal D2.

[0013] For example, if copy control information CC is generation limitedinformation of which the copy of only a first generation is allowed, theadditional information changing section 122 changes copy controlinformation by generating new copy control information the controlcontents of which represent the prohibition of copy and adding this newcopy control information to the digital information signal D2.

[0014] As a result, as described above, a digital information signal D3to which copy control information changed if necessary is added and copycontrol information CC are output from the additional informationchanging section 122 and sent to a writing section 123.

[0015] The writing section 123 converts the above digital readinformation signal D3 to digital information suitable for recording ifcopy control information CC supplied via the additional informationchanging section 122 represents the allowance of recording a digitalread information signal from the digital information reading device 110and writes the above converted digital information to a recording medium124. In the meantime, if copy control information CC from the additionalinformation reading section 121 represents the prohibition of copy, thewiring section 123 does not record the above digital read informationsignal D3.

[0016] Further, if copy control information CC from the additionalinformation reading section 121 represents that the copy of only a firstgeneration is allowed, the digital read information signal D3 to whichnew copy control information is added by the additional informationchanging section 122 as described above is converted to digitalinformation suitable for recording and is written to the recordingmedium 124. In this case, a digital information signal cannot be copiedusing a copied recording medium 124.

[0017] As described above, in the case of so-called digital connectionthat a main information signal and copy control information asadditional information are supplied to the recording device as a digitalsignal, the recording device can securely execute copy preventingcontrol such as the prohibition of copy using copy control informationbecause copy control information is included in transmitted digitaldata.

[0018] As described above, even if information recorded in a recordingmedium in which a digital video signal as a main information signal andcopy control information as additional information are recorded is readusing a digital reading device and copy control information is obtainedtogether with a digital video signal, only a digital video signal whichis a main information signal can be converted to an analog signal via aD/A converting circuit to monitor an image for example and can be outputto an analog output terminal to which a picture tube of a monitor isnormally connected.

[0019] As described above, even if digital information is read by areading device, a copy control signal is not included in an analogsignal output to the analog output terminal. Therefore, in the case ofanalog connection in which analog VTR and others are connected to ananalog output terminal, control over copy based upon copy controlinformation is disabled, for example the copy of a main informationsignal the copy of which is prohibited is enabled and the limitation ofa generation of copy is also disabled.

[0020] As copy control information is often added in a header and othersseparately from a digital video signal as a main information signal evenin the case of digital connection, copy control based upon copy controlinformation is disabled and illegal copy is enabled by deletinginformation in a part to which copy control information is added andfalsifying copy control information such as replacing with anotherinformation.

[0021] Further, it is also conceivable that when copy controlinformation is superimposed or added in a frequency band different fromthe frequency band of these video signal and aural signal even if avideo signal and an aural signal respectively as a main informationsignal are an analog signal or a digital signal, copy controlinformation is deleted by a simple frequency filter and copy controlbased upon copy control information is disabled.

[0022] Therefore, as described above referring to FIG. 1, as the signalstrength of additional information such as copy control informationadded to a main information signal is weak and additional informationcannot be regenerated in case it is once deleted even if more flexiblecopy control is executed by providing a function for changing copycontrol information as additional information to the recording device,changing additional information added to an information signal inrecording an information signal if necessary and utilizing the changedadditional information, a case that additional information added to aninformation signal cannot be sufficiently utilized occurs.

SUMMARY OF THE INVENTION

[0023] The present invention is made in view of the above problems andthe object is to enable adding additional information to an informationsignal without deteriorating the quality of a read information signal sothat falsification and deletion are disabled also in a device used by ageneral user, detecting additional information added to an informationsignal if necessary and utilizing the additional information.

[0024] An information signal processing unit according to the presentinvention is characterized in that it is provided with reading means forreceiving an information signal on which an additional informationsignal the spectrum of which is spread is superimposed and reading theabove additional information signal from the above information signal,additional information signal generating means for generating a newadditional information signal based upon the additional informationsignal read by the reading means, spreading means for spreading thespectrum of the new additional information signal generated by theadditional information signal generating means and superposing means forsuperposing the new additional information signal the spectrum of whichis spread by the spreading means on the above information signal andoutputting it.

[0025] According to the above unit, the spectrum of a new additionalinformation signal is spread, is superimposed on a digital informationsignal as a wide-band and low-level signal and if the digitalinformation signal is a video signal, the superimposed additionalinformation signal never deteriorates a reproduced image.

[0026] Further, as the new additional information signal is superimposedon the digital information signal at the same time and in the samefrequency band, it is difficult to falsify or delete additionalinformation by a frequency filter or the simple replacement ofinformation signals.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a block diagram showing an example of a conventionaltype copying device;

[0028]FIG. 2 is a block diagram for explaining an embodiment of aninformation signal recording device according to the present invention;

[0029]FIG. 3 is a block diagram for explaining a timing generatingsection in the recording device shown in FIG. 2;

[0030]FIG. 4 is a block diagram for explaining an SS additionalinformation generating section in the recording device shown in FIG. 2;

[0031]FIG. 5 is a block diagram for explaining an example of a PN codegenerating section in a part of the SS additional information generatingsection shown in FIG. 4;

[0032] FIGS. 6 show relationship between SS additional information (copycontrol information) and an information signal in the shape of aspectrum;

[0033]FIG. 7 is a block diagram for explaining an embodiment of aninformation signal recording system according to the present invention;

[0034]FIG. 8 is a block diagram for explaining another example of the SSadditional information generating section;

[0035]FIG. 9 is a block diagram for explaining further another exampleof the SS additional information generating section;

[0036]FIG. 10 is a block diagram for explaining the other example of theSS additional information generating section;

[0037]FIG. 11 is a block diagram showing an example of an SS additionalinformation detecting section; and

[0038]FIG. 12 is a block diagram showing another example of the SSadditional information detecting section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Referring to the drawings, embodiments of the present inventionwill be described below.

First Embodiment

[0040]FIG. 2 is a block diagram for explaining an information signalrecording device 10 equivalent to a first embodiment (hereinafter calledonly a recording device). The recording device 10 equivalent to thefirst embodiment receives a digital information signal provided via anetwork such as the Internet and records it on a recording medium. Thatis, the recording device 10 is obtained by applying the presentinvention to a device such as a personal computer which can send andreceive an information signal via a network such as the Internet.

Recording Device 10

[0041] As shown in FIG. 2, the recording device 10 equivalent to thefirst embodiment is provided with an additional information readingsection 11, a new additional information generating section 12, a timinggenerating section 13, a spread spectrum (SS) additional informationgenerating section 14, a signal superimposing section 15 and a writingsection 16.

[0042] A recording medium 100 is a disc such as CD-ROM and DVD to whichvarious digital information signals such as a digital video signal, adigital aural signal and a program are written by the recording device10. Hereinafter, to simplify description, a digital information signalsupplied to the recording device 10 and recorded on the recording medium100 shall be a digital video signal.

[0043] Additional information is added to a digital video signal S1supplied to the recording device 10 in the first embodiment. Theadditional information is 1- or 2-bit copy control informationrepresenting the contents of copy control over a digital video signal S1such as the allowance or prohibition of copy and the limitation of ageneration.

[0044] In the first embodiment, for example, a digital video signal S1sent via a network such as the Internet and received by the recordingdevice 10 is supplied to the additional information reading section 11of the recording device 10 and the timing generating section 13.

[0045] The additional information reading section 11 reads additionalinformation FS which is copy control information added to a digitalvideo signal S1 from the digital video signal S1, supplies it to the newadditional information generating section 12 and supplies the digitalvideo signal S1 to the signal superimposing section 15 as it is.

[0046] The new additional information generating section 12 generatesnew additional information FS1 (hereinafter called new additionalinformation) to be added to the digital video signal S1 based upon theadditional information FS from the additional information readingsection 11.

[0047] In the first embodiment, for example, when additional informationFS from the additional information reading section 11 represents theallowance of the copy of only a first generation, the new additionalinformation generating section 12 generates new additional informationFS1 representing the prohibition of copy. When additional information FSfrom the additional information reading section 11 represents theprohibition or the allowance of copy, the new additional informationgenerating section 12 supplies the additional information FSrepresenting the prohibition or the allowance of copy to the SSadditional information generating section 14 as new additionalinformation FS1 as it is.

[0048] When additional information FS is not read from the digital videosignal S1 by the additional information reading section 11 such asadditional information is not added to the digital video signal S1, thenew additional information generating section 12 detects the above,generates additional information FS1 based upon the number of therecording device 10 such as the serial number of the recording device 10or ID number of a user of the recording device 10 and supplies it to theSS additional information generating section 14. In the recording device10 equivalent to the first embodiment, these number of the recordingdevice 10 and ID number of a user are recorded beforehand in a memorywith which the new additional information generating section 12 isprovided.

[0049] As described above, the new additional information generatingsection 12 generates new additional information FS1 based uponinformation obtained as a result of processing for reading additionalinformation by the additional information reading section 11 andsupplies it to the SS additional information generating section 14.

[0050] In the meantime, the timing generating section 13 receives thedigital video signal S1, detects a reference timing signal from thedigital video signal S1 and generates a timing signal TM and a clocksignal CLK respectively used in each section of the recording device 10equivalent to the first embodiment based upon the detected referencetiming signal.

[0051]FIG. 3 is a block diagram for explaining the timing generatingsection 13 of the recording device 10 equivalent to the firstembodiment. As shown in FIG. 3, the timing generating section 13 isprovided with a reference timing detecting section 131, a phase-lockedloop (PLL) circuit 132 and a timing signal generating section 133.

[0052] The reference timing detecting section 131 extracts asynchronizing signal DK as a reference timing signal from the digitalvideo signal S1 supplied to the reference timing detecting section andsupplies it to the PLL circuit 132 and the timing signal generatingsection 133.

[0053] The PLL circuit 132 generates a clock signal CLK synchronizedwith the digital video signal S1 based upon a synchronizing signal DKfrom the reference timing detecting section 131. The clock signal CLK issupplied to the timing signal generating section 133 and each sectionusing the clock signal CLK such as the SS additional informationgenerating section 14 described later.

[0054] The timing signal generating section 133 generates and outputs atiming signal TM used by the SS additional information generatingsection 14 described later and the other various timing signals basedupon a synchronizing signal DK from the reference timing detectingsection 131 and a clock signal CLK from the PLL circuit 131.

[0055] In the first embodiment, a timing signal TM generated by thetiming signal generating section 133 is used for a reset (initializing)signal synchronized with a synchronizing signal DS from the referencetiming detecting section 131 and showing timing for generating a newadditional information string the spectrum of which is spread and apseudorandom noise (PN) code string provided with a predetermined codepattern used for spreading a spectrum from the head in the SS additionalinformation generating section 14 described later.

[0056] For example, if it is set that the reference timing detectingsection 131 of the timing generating section 13 extracts a verticalsynchronizing signal as a reference timing signal, a clock signal CLKsynchronized with a vertical synchronizing signal from the referencetiming detecting section 131 is generated by the PLL circuit 132.

[0057] The timing signal generating section 133 generates a timingsignal TM set so that one vertical interval (one field) is equivalent toone cycle and synchronized with a vertical synchronizing signal used fora reference timing signal based upon a vertical synchronizing signalfrom the reference timing detecting section 131 and a clock signal CLKfrom the PLL circuit 132.

[0058] A timing signal TM and a clock signal CLK respectively generatedby the timing generating section 13 as described above are supplied tothe SS additional information generating section 14 as shown in FIG. 2.

[0059] The SS additional information generating section 14 receives newadditional information FS1, a timing signal TM and a clock signal CLKand generates spread spectrum additional information SF1 which is aspread spectrum signal of the new additional information FS1.

[0060]FIG. 4 is a block diagram for explaining the SS additionalinformation generating section 14 in the first embodiment. As shown inFIG. 4, the SS additional information generating section 14 is providedwith a PN code generating section 141 and a multiplying section 142.

[0061] The PN code generating section 141 generates a PN code string PSbased upon a timing signal TM and a clock signal CLK. That is, in thefirst embodiment, the PN code generating section 141 generates a PN codestring PS from the head in synchronization with a clock signal CLK everytime a timing signal TM is supplied and supplies it to the multiplyingsection 142.

[0062] A new additional information string FS1R composed of each bit ofnew additional information FS1 from the new additional informationgenerating section 12 output by the predetermined number of clocks insynchronization with a clock signal CLK at timing shown by a timingsignal TM is supplied to the multiplying section 142.

[0063] The multiplying section 142 generates a spread spectrum signal(SS additional information) SF1 which is new additional information thespectrum of which is spread by multiplying the PN code string PS and thenew additional information string FS1R.

[0064] As described above, the SS additional information generatingsection 14 is provided with a function as spreading means for convertingnew additional information FS1 with a narrow band and at a high level toSS additional information SF1 with a wide band and at a low level asalso described later by spreading the spectrum of additional informationFS1 using the PN code string PS.

[0065]FIG. 5 shows an example of the constitution of the PN codegenerating section 141 shown in FIG. 4. The PN code generating section141 in this example is composed of 12 D flip-flop circuits REG1 to REG15constituting 12 shift registers and exclusive OR circuits WX-OR1 toEX-OR3 for operating the suitable tap output of the shift register. ThePN code generating section 141 shown in FIG. 4 generates an M series ofPN code string PS based upon a timing signal TM and a clock signal CLKas described above.

[0066] An enabling signal EN in FIG. 5 is a signal for operating the PNcode generating section 141 and in the first embodiment, the aboveenabling signal is generated when the recording device 10 shown in FIG.2 for example is powered on and is supplied to the PN code generatingsection 141.

[0067] SS additional information SF1 obtained from the SS additionalinformation generating section 14 as described above is supplied to thesignal superimposing section 15.

[0068] The signal superimposing section 15 receives a digital videosignal S1 and digital SS additional information SF1 and generates adigital video signal S2 on which the digital SS additional informationSF1 is superimposed.

[0069] The signal superimposing section 15 superposes SS additionalinformation SF1 on the least significant bit (LSB) of a 10-bit digitalvideo signal and a ninth bit which is a bit next to the leastsignificant bit in case the digital video signal S1 is composed of tenbits which represent an image equivalent to one picture element forexample. As described above, the signal superimposing section 15superposes SS additional information SF1 on the digital video signal S1at the same time and in the same frequency band.

[0070] In this case, the signal superimposing section 15 prevents SSadditional information SF1 from deteriorating the digital video signalS1 by superimposing SS additional information SF1 on the digital videosignal S1 by signal power lower than the dynamic range of the digitalvideo signal S1. A digital video signal S2 generated by superimposing SSadditional information SF1 on the digital video signal S1 by the signalsuperimposing section 15 as described above is supplied to the writingsection 16.

[0071] The writing section 16 receives the digital video signal S2 onwhich the digital SS additional information SF1 is superimposed,converts it to a digital video signal for recording suitable forrecording and writes the digital video signal for recording to therecording medium 100. Hereby, the digital video signal on which the SSadditional information SF1 which is new additional information thespectrum of which is spread is superimposed is recorded in the recordingmedium 100 in addition to the additional information FS added before.

[0072] As described below, as the spectrum of new additional informationFS1 superimposed on the digital video signal recorded on the recordingmedium 100 is spread, an image reproduced by the digital video signal isnever deteriorated and falsification and deletion are disabled.

[0073] Therefore, if a digital video signal recorded on the recordingmedium 100 is read or a digital video signal read from the recordingmedium 100 is recorded (copied) on another recording medium, newadditional information superimposed on a digital video signal can besecurely obtained and utilized such as new additional information thespectrum of which is spread and superimposed on the digital video signalis extracted and copy control is executed according to the newadditional information.

[0074] FIGS. 6 show relationship between additional information which isinformation such as copy control information and an information signal,a video signal in this example in the shape of a spectrum. The quantityof information included in additional information is small, additionalinformation is a signal the bit rate of which is slow and as shown inFIG. 6A, is a narrow-band signal. When the spectrum of the signal isspread, the signal becomes a wide-band signal as shown in FIG. 6B. Atthis time, the level of a spread spectrum signal is lowered in inverseproportion to the extension of the band.

[0075] The spread spectrum signal, that is, the SS additionalinformation SF1 is superimposed on an information signal by the signalsuperimposing section 15, however, in this case, as shown in FIG. 6C,the SS additional information SF1 is superimposed at a lower level thanthe dynamic range of a video signal as an information signal. Thedeterioration of an information signal can be mostly prevented bysuperimposing as described above. Therefore, if a video signal on whichSS additional information SF1 is superimposed is supplied to a picturetube of a monitor and an image is reproduced, the image is hardlyinfluenced by the SS additional information SF1 and a satisfactoryreproduced image can be obtained.

[0076] However, as described later, when the spectrum of SS additionalinformation SF1 is reduced to detect the SS additional information SF1in a recording device, the SS additional information SF1 is restoredagain as a narrow-band signal (additional information) as shown in FIG.6D. The power of copy control information after the spectrum is reducedis higher than the power of an information signal by applying asufficient spread spectrum factor and the copy control information canbe detected.

[0077] In this case, as SS additional information SF1 is superimposed ona video signal at the same time and in the same frequency band, thedeletion and modification of the SS additional information are disabledby a frequency filter and the simple replacement of information.

[0078] As described above, if a digital video signal is read from therecording medium 100 or a read digital video signal is recorded onanother recording medium, new additional information the spectrum ofwhich is spread and superimposed is extracted and copy preventingcontrol according to the extracted additional information can beexecuted.

[0079] If new additional information the spectrum of which is spread andsuperimposed is extracted from a digital video signal, new additionalinformation is generated in synchronization with the same PN code stringas a PN code string for spreading a spectrum and new additionalinformation the spectrum of which is spread and superimposed on thedigital video signal can be extracted by reducing the spectrum using thePN code string.

[0080] As described above, the recording device 10 equivalent to thefirst embodiment generates new additional information based uponinformation obtained by reading additional information added to adigital video signal in case the supplied digital video signal isrecorded on a recording medium. A digital video signal on which newadditional information the spectrum of which is spread is superimposedobtained by spreading the spectrum of the above new additionalinformation and superimposing the new additional information on thedigital video signal can be recorded on a recording medium.

[0081] As described above, as the spectrum of new additional informationsuperimposed on a digital video signal is spread and the new additionalinformation is superimposed as a wide-band signal at a low level, avideo signal read by the digital video signal is never deteriorated.

[0082] As new additional information the spectrum of which is spread issuperimposed on a digital video signal at the same time and in the samefrequency band, the new additional information cannot be falsified ordeleted by a frequency filter or the replacement of an informationsignal.

[0083] As described above, as new additional information the spectrum ofwhich is spread is superimposed on a digital video signal at the sametime and in the same frequency band, additional information is neverdeleted even if the digital video signal on which the additionalinformation the spectrum of which is spread is superimposed is convertedfrom a digital signal to an analog signal.

[0084] Therefore, when a digital video signal on which new additionalinformation the spectrum of which is spread is superimposed is read orcopied, additional information superimposed on the digital video signalis extracted, copy control according to the additional information isexecuted, the contents of the additional information are updated and newadditional information is generated, the new additional information isadded again and more flexible control such as the limitation of ageneration is enabled. As described above, new additional informationsuperimposed on a digital video signal can be securely obtained andutilized.

[0085] As described above, for new additional information FS1 generatedby the new additional information generating section 12, new additionalinformation FS1 may be also generated by changing additional informationFS from the additional information reading section, additionalinformation FS may be also used for new additional information FS1 as itis, different new additional information FS1 from additional informationFS may be also generated or a part of additional information FS ischanged and it may be also used for new additional information FS1.

[0086] Additional information FS and new additional information FS1 mayalso represent the same contents and may also represent separatecontents. As described above, if additional information and newadditional information represent separate contents, the quantity ofadditional information which can be added to a digital video signalwhich is an information signal to be recorded on a recording medium canbe increased.

[0087] Additional information FS read by the additional informationreading section 11 is supplied to the writing section 16 and copycontrol according to the additional information SF may be also executedby the writing section 16.

[0088] If the processing such as coding of a digital video signal to berecorded is required, the processing may be executed by the writingsection 16.

Second Embodiment

[0089]FIG. 7 is a block diagram for explaining an information signalcopy system equivalent to a second embodiment. The information signalcopy system equivalent to the second embodiment is constituted by aninformation signal reading device 20 connected via a network such as theInternet (hereinafter called only a reading device) and an informationsignal recording device 30 (hereinafter called only a recording device)as in the above first embodiment. These reading device 20 and recordingdevice 30 are applied to a device such as a personal computer which cansend or receive an information signal via a network such as theInternet.

Reading Device 20

[0090] As shown in FIG. 7, the reading device 20 is provided with areading section 21 and provided with a function as an information signalsending device for reading and sending an information signal recorded ona recording medium 200. In the second embodiment, the recording medium200 is a disc information on which can be read by the reading device 20such as CD-ROM and DVD.

[0091] In the second embodiment, a digital video signal is recorded onthe recording medium 200. A digital video signal recorded on therecording medium 200 is recorded by the recording device 10 in the firstembodiment for example.

[0092] Therefore, first additional information the spectrum of which isspread is superimposed on a digital video signal at the same time and inthe same frequency band and recorded on the recording medium 200 andsecond additional information is added in another recording area on atrack on which video data is to be recorded. That is, two types ofadditional information different in an adding method is superimposed andadded on/to a digital video signal recorded on the recording medium 200.

[0093] The reading section 21 of the reading device 20 generates adigital read video signal S12 based upon a signal S11 obtained byreading information on the recording medium 200 and sends it to therecording device 30 via a network such as the Internet.

[0094] In this case, as described above, the spectrum of the firstadditional information is spread to be a wide-band signal at a low leveland the first additional information is superimposed on a digital videosignal at the same time and in the same frequency band.

[0095] Therefore, the first additional information never deteriorates animage reproduced based upon the digital video signal and is neverfalsified or deleted. Even if a digital video signal on which additionalinformation 1 the spectrum of which is spread is superimposed isconverted to an analog signal, the first additional information is neverdeleted.

[0096] Therefore, the first additional information the spectrum of whichis spread and superimposed on a digital video signal is securelyprovided to the recording device 30 together with the digital videosignal.

Recording Device 30

[0097] The recording device 30 in the second embodiment is provided witha function as an information signal receiving device for receiving andprocessing an information signal provided via a network such as theInternet. The recording device 30 in the second embodiment is providedwith an SS additional information reading section 31, a new additionalinformation generating section 32, a timing generating section 33, an SSadditional information generating section 34, a signal superimposingsection 35, a writing section 36 and an additional informationreading/changing section 37 as in FIG. 7.

[0098] Each section except the SS additional information reading section31 and the additional information reading/changing section 37 is thesame as the corresponding each section of the recording device 10 in theabove first embodiment.

[0099] A digital read video signal S12 from the reading device 20 issupplied to the SS additional information reading section 31 and thetiming generating section 33 respectively of the recording device 30.

[0100] The timing generating section 33 is provided with the sameconstitution as that of the timing generating section 13 in the firstembodiment described referring to FIG. 3 and generates a timing signalTm and a clock signal CLK used in each section of the recording device30. Therefore, the timing generating section 33 will be explainedassuming that it is provided with the constitution shown in FIG. 3.

[0101] A reference timing detecting section 131 of the timing generatingsection 33 extracts a synchronizing signal DK as a reference timingsignal from a digital video signal S12 from the reading device 20. Thesynchronizing signal DK is supplied to a PLL circuit 132 and a timingsignal generating section 133.

[0102] The PLL circuit 132 generates a clock signal CLK synchronizedwith a digital video signal S12 based upon a synchronizing signal DKfrom the reference timing detecting section 131 and supplies it to thetiming signal generating section 133, the SS additional informationreading section 31, the SS additional information generating section 34and others.

[0103] The timing signal generating section 133 generates and outputs atiming signal TM and other various timing signals used by the SSadditional information reading section 31, the SS additional informationgenerating section 34 and others based upon a synchronizing signal DKfrom the reference timing detecting section 131 and a clock signal CLKfrom the PLL circuit 132.

[0104] In the second embodiment, these timing signal TM and clock signalCLK provide the same timing as a timing signal TM and a clock signal CLKused by the recording device 10 equivalent to the first embodiment.

[0105] As described above, a timing signal TM and a clock signal CLKgenerated by the timing generating section 33 are supplied to the SSadditional information reading section 31 and the SS additionalinformation generating section 34 as shown in FIG. 7.

[0106] The SS additional information reading section 31 reduces thespectrum of a digital read video signal S12, extracts first additionalinformation F1 spectrum of which is spread and superimposed on thedigital read video signal S12, supplies it to the new additionalinformation generating section 32 and supplies the digital read videosignal S12 to the additional information reading/changing section 37 asit is.

[0107] That is, the SS additional information reading section 31 isprovided with a PN code generator and a multiplying section respectivelynot shown and provided with functions for generating a PN code stringfor reducing a spectrum with the same code pattern as that of a PN codestring used for spreading the spectrum of first additional informationthe spectrum of which is spread and superimposed on a digital videosignal S12 at the same timing based upon a timing signal TM and a clocksignal CLK from the timing generating section 33 and for extracting thefirst additional information F1 by reducing the spectrum using this PNcode string for reducing a spectrum.

[0108] The new additional information generating section 32 generatesfirst new additional information F12 added to a digital video signal tobe recorded on a recording medium 300 (hereinafter called first newadditional information) based upon additional information F1 from theadditional information reading section 31 and supplies it to the SSadditional information generating section 34 and the additionalinformation reading/changing section 37.

[0109] When additional information F1 supplied to the new additionalinformation generating section 32 allows the copy of only a firstgeneration, the new additional information generating section 32generate and outputs first new additional information F12 representingthe prohibition of copy as the new additional information generatingsection 12 in the first embodiment. When additional information F1represents the prohibition or the allowance of copy, the additionalinformation F1 representing the prohibition or the allowance of copy isoutput as it is as first new additional information F12.

[0110] When additional information F1 is not read from a digital videosignal S12 by the SS additional information reading section 31 such asin case SS additional information is not added to the digital videosignal S12, the new additional information generating section 32 detectsit, generates and outputs the serial number of the recording device 30,ID number of a user of the recording device 10 for example and others asfirst new additional information F12. New additional information forgenerating these is recorded in a memory with which the new additionalinformation generating section 32 is provided beforehand.

[0111] As described above, the new additional information generatingsection 32 generates first new additional information F12 based uponinformation obtained as a result of reading additional information bythe SS additional information reading section 31 and supplies it to theSS additional information generating section 34 and the additionalinformation reading/changing section 37.

[0112] The additional information reading/changing section 37 extractssecond additional information added to video data from a digital videosignal S12. The additional information reading/changing section 37generates second new additional information based upon the extractedsecond additional information and first new additional information F12from the new additional information generating section 32 (hereinaftercalled second new additional information) and adds it to the digitalvideo signal S12 again.

[0113] In this case, the second new additional information is added tovideo data constituted by digital video signals S12. Hereby, in thesecond embodiment, second additional information added to a digitalvideo signal S12 is rewritten to second new additional information. Adigital vide signal S13 generated by adding the second new additionalinformation by the additional information reading/changing section 37 issupplied to the signal superimposing section 35.

[0114] In the meantime, the SS additional information generating section34 is constituted as the SS additional information generating section 14in the first embodiment, receives new additional information F12, atiming signal TM and a clock signal CLK and generates SS additionalinformation SF12 which is a signal obtained by spreading the spectrum ofnew additional information F12. Therefore, the SS additional informationgenerating section 34 in the second embodiment is provided with the sameconstitution as that shown in FIG. 4.

[0115] As shown in FIG. 4, the SS additional information generatingsection 34 is provided with a PN code generating section 141 and amultiplying section 142.

[0116] The PN code generating section 141 of the SS additionalinformation generating section 34 is provided with the constitutiondescribed referring to FIG. 5 and generates a PN code string PS basedupon a timing signal TM and a clock signal CLK. That is, the PN codegenerating section 141 generates a PN code string PS from the head everytime a timing signal TM is supplied in synchronization with a clocksignal CLK and supplies it to the multiplying section 142.

[0117] A new additional information string F12R generated by outputtingeach bit of first new additional information F12 from the new additionalinformation generating section 32 by the predetermined number of clocksevery time a timing signal TM is output in synchronization with a clocksignal CLK is supplied to the multiplying section 142.

[0118] The multiplying section 142 generates a spread spectrum signal(SS additional information) SF12 which is first new additionalinformation the spectrum of which is spread by multiplying a PN codestring PS and a first new additional information string F12R andsupplies it to the signal superimposing section 35.

[0119] The signal superimposing section 35 receives a digital videosignal S13 to which second new additional information is added anddigital SS additional information SF12 and generates a digital videosignal S14 on which the digital SS additional information SF12 issuperimposed.

[0120] The signal superimposing section 35 superposes SS additionalinformation SF12 on a digital video signal S13 at the same time and inthe same frequency band as the signal superimposing section 15 in thefirst embodiment. In this case, the SS additional information SF12 issuperimposed on the digital video signal S1 by signal power

[0121] S1 lower than the dynamic range of the digital video signal Asdescribed above, a digital video signal S14 generated by the signalsuperimposing section 35 by superimposing the SS additional informationSF12 on the digital video signal S13 is supplied to the writing section36.

[0122] The writing section 36 receives the digital video signal S14,converts it to a digital video signal for recording suitable forrecording and writes the digital video signal for recording to therecording medium 300. Hereby, the digital video signal to which thesecond new additional information is added and on which the first newadditional information the spectrum of which is spread is superimposedis recorded on the recording medium 300.

[0123] In the second embodiment, it is described that the first newadditional information superimposed on the digital video signal as SSadditional information SF12 is generated based upon the first additionalinformation the spectrum of which is spread and superimposed on thedigital video signal S12, however, the present invention is not limitedto this.

[0124] For example, first new additional information may be alsogenerated based upon information obtained by reading first additionalinformation by the SS additional information reading section 31 andinformation obtained by reading second additional information by theadditional information reading/changing section 37 and first newadditional information may be also generated based upon only informationobtained by reading second additional information by the additionalinformation reading/changing section 37.

[0125] It is described above that the second new additional informationis generated based upon the first new additional information F12 and thesecond additional information, however, the present invention is notlimited to this. For example, the above second new additionalinformation may be also generated based upon information obtained byreading the first additional information by the SS additionalinformation reading section 31 and may be also generated based uponinformation obtained by reading second additional information by theadditional information reading/changing section 37.

[0126] As described above, second new additional information may be alsogenerated based upon first new additional information generated basedupon information obtained by reading first additional information by theSS additional information reading section 31 and information obtained byreading second additional information by the additional informationreading/changing section 37 and information obtained by reading thesecond additional information by the additional informationreading/changing section 37.

[0127] First and second additional information may be also superimposedand added on/to a digital video signal as first and second newadditional information as they are without generating first and secondnew additional information.

[0128] Another information different from the first and secondadditional information is generated, may be also added as additionalinformation, a part of original first and second additional informationis changed and may be also superimposed or added on/to a digital videosignal.

[0129] If the spectrum of first new additional information is spread andthe spread spectrum first new additional information is superimposed ona digital video signal using a PN code string different from a PN codestring used for spreading the spectrum of additional information thespectrum of which is spread and added to a digital read video signal S12the SS additional information generating section 34, for example PN codestrings different in a phase even if the PN code strings belong to thesame series and PN code strings different in a series, the spreadspectrum first new additional information can be superimposed on aninformation signal without being mistaken for the already superimposedspread spectrum first additional information and if necessary, can beextracted.

[0130] In the second embodiment, it is described that the spectrum offirst new additional information is spread and the spread spectrum firstnew additional information is superimposed on a digital video signal,however, the present invention is not limited to this, SS additionalinformation for negating spread spectrum first additional informationsuperimposed on a digital video signal is generated and after the spreadspectrum first additional information already superimposed is deleted bysubtracting the above first additional information from the digitalvideo signal, the spectrum of first new additional information may bealso spread and superimposed.

[0131] As described above, in the case of an information signalrecording control system in the second embodiment, the recording of adigital video signal can be controlled based upon first additionalinformation the spectrum of which is spread and superimposed on thedigital video signal and information obtained by detecting secondadditional information added to video data composed of digital videosignals and new additional information can be superimposed and addedon/to a digital video signal to be recorded on a recording medium 400.

Other Examples of SS Additional Information Generating Section

[0132] In the above embodiments, as described referring to FIG. 4, theSS additional information generating sections 14 and 34 spread thespectrum of additional information composed of small bits such as oneand two bits by one PN code and generate SS additional information SF1and SF12, however, as described below, the spectrum of additionalinformation is not spread but a PN code itself or a mixture of a PN codeand another code may be also superimposed on a digital video signal asadditional information representing the contents of copy control.

[0133] In the above description, additional information FS is equivalentto new additional information FS1 and F12 generated by the above newadditional information generating sections 12 and 32 and SS additionalinformation SF is equivalent to spread spectrum signals (SS additionalinformation) SF1 and SF12 the spectrum of which is spread by the SSadditional information generating sections 14 and 34.

[0134]FIG. 8 shows an embodiment of the SS additional informationgenerating section using PN codes different in a phase.

[0135] In the embodiment, a PN code PS output from a PN code generatingsection 1001 is supplied to a selecting section 1003 and is supplied toa shift register 1002. PN codes PSa, PSb, ---, PSn obtained bysequentially shifting a PN code PS according to a clock signal andrespectively different in a phase are output from the shift register1002 and are respectively supplied to the selecting section 1003.

[0136] Additional information FS as a selection control signal issupplied to the selecting section 1003. The selecting section 1003selects a PN code of one phase according to the contents of controlrepresented in additional information FS which is a selection controlsignal, that is, the prohibition or the allowance of copy out of PNcodes PS, PSa, PSb, ---, PSn of plural phases and outputs it as SSadditional information SF.

[0137]FIG. 9 shows an embodiment of the SS additional informationgenerating section using PN codes different in a series.

[0138] In the embodiment, plural PN code generators 1021, 1022 and 1023for generating PN codes PS1, PS2 and PS3 different in a series areprovided. Output from each PN code generator 1021, 1022 and 1023 isinput to the selecting section 1024.

[0139] Additional information FS is supplied to the selecting section1024 as a selection control signal. The selecting section 1024 selects aPN code of one series according to the contents of control representedin additional information FS which is a selection control signal, thatis, the prohibition or the allowance of copy out of PN codes PS1, PS2and PS3 of plural series and outputs it as SS additional information SF.

[0140]FIG. 10 shows an embodiment of the main part of an SS additionalinformation generating/superimposing device in case one type of PN codeand plural orthogonal codes are used.

[0141] In the embodiment, one PN code generating section 1041 andorthogonal code generating sections 1042, 1043 and 1044 for respectivelygenerating orthogonal codes mutually different are provided. A PN codePS output from the PN code generating section 1041 is input to amultiplying section 1046. Different orthogonal codes respectively fromthe orthogonal code generating sections 1042, 1043 and 1044 are input tothe selecting section 1045. Additional information FS is supplied to theselecting section 1045 as a selection control signal.

[0142] The selecting section 1045 outputs one orthogonal code accordingto the contents of control represented in additional information FSwhich is a selection control signal, that is, the prohibition or theallowance of copy out of plural different orthogonal codes to themultiplying section 1046. The multiplying section 1046 multiplies theabove PN code PS and the selected orthogonal code and outputs the resultof the multiplication as SS additional information SF.

Detecting SS Additional Information Corresponding Other Examples of SSAdditional Information Generating Section

[0143] If the SS additional information generating sections respectivelyshown in FIGS. 8 to 10 are used, the detection of spread spectrumadditional information is executed as follows:

[0144]FIG. 11 shows an example of an SS additional information detectingsection for detecting additional information from a video signal onwhich SS additional information for which PN codes of different phasesshown in FIG. 8 are used is superimposed.

[0145] In the SS additional information detecting section in thisexample, a digital read video signal (a received signal) on which SSadditional information is superimposed is input to a PN code detectingsection 1061. In the PN code detecting section 1061, the timing of a PNcode is detected and the result is input to an additional informationgenerating section 1062. The additional information generating section1062 specifies the contents of copy control represented in additionalinformation based upon difference in timing between PN codes, generatesadditional information to be supplied to a recording control sectionaccording to the result of the specification and outputs it.

[0146]FIG. 12 shows an example of an SS additional information detectingsection for detecting additional information from a vide signal on whichSS additional information for which PN codes of different series shownin FIG. 9 or a mixture of one type of PN code and plural orthogonalcodes shown in FIG. 10 are used is superimposed.

[0147] In the SS additional information detecting section in thisexample, a digital video signal on which SS additional information issuperimposed (a received signal) is input to PN code detecting sections1081, 1082 and 1083. The PN code detecting sections 1081, 1082 and 1083respectively detect a different PN code or a code obtained bymultiplying one type of PN code and a different orthogonal code. Theoutput is input to an additional information generating section 1084.The additional information generating section 1084 specifies the type ofadditional information based upon which code string is detected,generates additional information to be supplied to a recording controlsection according to the result of the specification and outputs it.

[0148] If the above SS additional information generating section and theabove SS additional information detecting section are used, pluraldifferent additional information can be also simultaneously added byusing PN codes of different phases or a code obtained by combining anorthogonal code and a PN code in spreading the spectrum of additionalinformation showing the contents of copy control and to be superimposed.

[0149] In the above first and second embodiments, a PN code of M seriesis used, however, the present invention is not limited to this andvarious spreading codes such as a code of a gold code series may beused.

[0150] In the above first and second embodiments, a timing signal and aclock signal are generated using a synchronizing signal extracted from adigital video signal for a reference signal, however, the presentinvention is not limited to this.

[0151] Various timing used by each section of the recording devices 10and 30 in the above first and second embodiments may be also controlledby a system controller for example without using a synchronizing signalfrom a digital video signal as a reference signal.

[0152] In the above first and second embodiments, if the coding of adigital video signal as an information signal and the compression of asignal are required, the above coding and compression can be executed bythe reading section 21 of the recording device and the writing sections16 and 36 of the recording device.

[0153] As described above, if 10-bit data is recorded in 8 bits forexample in case a digital video signal is compressed, the deteriorationand the deletion of SS additional information can be prevented bysuperimposing the SS additional information at the time of 10 bitsbefore compression even if the compressed digital video signal isrestored.

[0154] Also, if compression in which S-N ratio of a digital video signalis deteriorated for example is done, SS additional information can bealso inserted into higher order bits without limiting to low order bitssuch as LSB.

[0155] The above examples show a case that an information signal is adigital video signal, however, the present invention can be applied toan audio signal and various information signals in a computer programand others. An information signal may be also an analog signal withoutlimiting to a digital signal.

[0156] Additional information is not limited to copy control informationand various information such as control information, relatedinformation, the serial number of a recording device, ID of a user, arecorded date, an authorized number and copyright information can beadded and superimposed to/on an information signal.

[0157] In the above first and second embodiments, it is described thatthe recording mediums 100, 200 and 300 are a disc such as CD-ROM andDVD, however, they are not limited to CD-ROM and DVD.

[0158] For a recording medium, various recording mediums such as anoptical disc, a magneto-optical disc, a magnetic disc and a magneticrecording medium such as a video tape may be used.

[0159] In the above first and second embodiments, it is described thatthe recording devices 10 and 30 and the reading device 20 are a personalcomputer which sends and receives data via a network and others,however, the recording device and the reading device are not limited tothis.

[0160] The present invention can be applied to various recording devicesand recording/reading devices such as a recording device and arecording/reading device for DVD, digital VTR, VTR and a cassette taperecorder.

[0161] As described above, according to the information signal recordingdevice according to the present invention, as the frequency band ofadditional information is spread by spreading the spectrum and thespread spectrum additional information is superimposed on an informationsignal at the same time and in the same frequency band, thefalsification and the deletion of additional information are disabled bya frequency filter and the simple replacement of an information signal.Even if an information signal is a digital signal and it is converted toan analog signal, additional information can be prevented from beingdeleted. As described above, the survival rate of additional informationsuperimposed on an information signal can be enhanced.

[0162] As additional information the falsification and the deletion ofwhich are disabled and with high signal strength can be added to aninformation signal as described above, reliable devices and systems inwhich the deletion and others of additional information never occur canbe realized.

[0163] As the spectrum of additional information is spread to be awide-band and low-level signal, the additional information can besuperimposed on an information without deteriorating the informationsignal.

[0164] According to the information signal recording device according tothe present invention, as additional information of the same contents isadded in different adding methods, the reliability and strength ofadditional information added to an information signal can be enhanced.As falsification can be checked by equalizing additional informationadded to an information signal in different adding methods, a range inwhich additional information is utilized can be widened. Further,additional information different in contents can be also added to aninformation signal in different adding methods and in this case, thetotal quantity of additional information added to an information signalcan be increased.

[0165] According to the information signal recording device according tothe present invention, plural additional information can be also readilysimultaneously superimposed on the same information signal and utilizedby using spreading codes different in a phase or plural differentspreading codes such as a spreading code and an orthogonal code.

[0166] According to the information signal recording device according tothe present invention, as additional information the spectrum of whichis spread is superimposed on an information signal at a low signallevel, the additional information can be prevented from having an effectupon the information signal such as deteriorating the informationsignal.

[0167] According to the information signal recording device according tothe present invention, additional information can be promptly extractedby synchronizing a spreading code for spreading the spectrum ofadditional information and a spreading code for reducing the spectrumwhen the spectrum is reduced.

What is claimed is:
 1. An information signal processing unit,comprising: reading means for receiving a digital information signal onwhich an additional information signal the spectrum of which is spreadis superimposed and reading said additional information signal from saidinformation signal; additional information signal generating means forgenerating a new additional information signal based upon saidadditional information signal read by said reading means; spreadingmeans for spreading the spectrum of said new additional informationsignal generated by said additional information signal generating means;and superimposing means for superimposing said new additionalinformation signal the spectrum of which is spread by said spreadingmeans on said information signal and outputting it.
 2. An informationsignal processing unit as claimed in claim 1 , wherein: recording meansfor recording an output signal from said superimposing means isprovided.
 3. An information signal processing unit, comprising:additional information signal detecting means for receiving a digitalinformation signal to which a first additional information signal and asecond additional information signal are added and detecting said firstadditional information signal and said second additional informationsignal from said information signal; first additional information signalgenerating means for generating a first new additional informationsignal based upon said first additional information signal detected bysaid additional information signal detecting means; second additionalinformation signal generating means for generating a second newadditional information signal based upon said first new additionalinformation signal and said second additional information signal;addition means for adding said second new additional information signalto said information signal; and superimposing means for superimposingsaid first new additional information signal on said second additionalinformation signal from said addition means.
 4. An information signalprocessing unit as claimed in claim 3 , wherein: the spectrum of saidfirst additional information signal is spread; and said first additionalinformation signal is detected by reducing the spectrum by saidadditional information signal detecting means.
 5. An information signalprocessing unit as claimed in claim 4 , comprising: spreading means forspreading the spectrum of said first new additional information signal,wherein: said superimposing means superposes said first new additionalinformation signal the spectrum of which is spread on said informationsignal from said addition means.
 6. An information signal processingunit as claimed in claim 1 , comprising: recording means for recordingan output signal from said superimposing means is provided.